Residency · Residency · Child Adolescent Psychiatry
Tic Disorders and Tourette Syndrome in Youth
Introduction
Tic disorders are among the most common movement disorders in children, with Tourette syndrome (TS) representing the most complex and well-known presentation. Tics are sudden, rapid, recurrent, non-rhythmic motor movements or vocalizations. Although tics themselves often wax and wane and may remit by adulthood, the associated psychiatric comorbidities, particularly ADHD and OCD, frequently cause more functional impairment than the tics themselves.
Classification
DSM-5 Tic Disorders
Tourette syndrome requires the presence of both motor and vocal tics for more than one year with onset before age 18. Persistent or chronic motor or vocal tic disorder involves motor or vocal tics, but not both, for more than one year. Provisional tic disorder involves motor and/or vocal tics present for less than one year. Other specified and unspecified tic disorders cover presentations that do not meet full criteria for the above categories.
Types of Tics
Simple motor tics include eye blinking, head jerking, shoulder shrugging, and facial grimacing. Complex motor tics include jumping, touching, copropraxia (obscene gestures), and echopraxia. Simple vocal tics include sniffing, throat clearing, and grunting. Complex vocal tics include echolalia, palilalia, and coprolalia, though coprolalia is present in only 10-15% of patients with Tourette syndrome.
Epidemiology
Transient tics occur in 10-20% of school-age children. Tourette syndrome has a prevalence of approximately 0.3-1% of children. The male-to-female ratio is 3-4:1. The average age of onset is five to seven years. Tics typically peak in severity at ages 10-12 and improve in most individuals by late adolescence. Only 20-30% of individuals with Tourette syndrome have tics that persist as clinically significant in adulthood.
Neurobiology
Tic generation involves dysfunction in cortico-striato-thalamo-cortical circuits. Abnormalities in dopaminergic neurotransmission within the basal ganglia are central to the pathophysiology. Neuroimaging studies show reduced volume of the caudate nucleus. GABAergic interneuron dysfunction in the striatum contributes to the failure of inhibitory control. There is a strong genetic component, with heritability estimated at 60-80%. The PANDAS/PANS hypothesis proposes a post-infectious autoimmune mechanism for some acute-onset tic presentations, involving anti-basal ganglia antibodies.
Comorbidities
ADHD is present in 50-60% of youth with Tourette syndrome and is often the primary source of functional impairment. OCD co-occurs in 30-50% and often features symmetry, "just right" feelings, and counting compulsions. Anxiety disorders, including generalized anxiety, social anxiety, and separation anxiety, are common. Depression is often secondary to social stigma and functional impairment. Learning disabilities are present in 20-30%. Rage attacks and emotional dysregulation, characterized by episodic, explosive outbursts disproportionate to the trigger, are frequently reported. Sleep disturbances, including insomnia and restless sleep, are also common.
Assessment
Clinical History
The assessment should document the onset, course, waxing-waning pattern, and tic repertoire. The premonitory urge, a sensory phenomenon preceding tics that includes tension, itch, or discomfort, is present in most children over age ten. Suppressibility should be explored, as most patients can transiently suppress tics at the cost of increasing discomfort. Functional impact on school, social, and family life should be evaluated. A comprehensive assessment of comorbidities, particularly ADHD, OCD, and anxiety, is essential.
Rating Scales
The Yale Global Tic Severity Scale (YGTSS) is the gold standard for tic assessment. It evaluates the number, frequency, intensity, complexity, and interference of motor and vocal tics separately.
Differential Diagnosis
Stereotypies have an earlier onset, are more rhythmic, and are associated with ASD or intellectual disability. Myoclonus, dystonia, and chorea are neurological movement disorders that must be distinguished from tics. Functional or psychogenic tics typically have abrupt onset and an inconsistent pattern. Medication-induced movement disorders from stimulants or antipsychotics should be considered.
Treatment
Behavioral Interventions (First-Line)
Comprehensive Behavioral Intervention for Tics (CBIT) is the evidence-based, first-line treatment. It includes habit reversal training, which combines awareness training with competing response training, along with functional interventions to modify tic-exacerbating situations and relaxation training. Its efficacy is comparable to medication but without side effects. CBIT is recommended as the initial treatment for mild to moderate tics.
Pharmacotherapy
Pharmacotherapy is reserved for tics causing significant functional impairment that have not responded to CBIT. Guanfacine, an alpha-2 agonist, is first-line and also treats ADHD; sedation is the main side effect. Clonidine, another alpha-2 agonist, causes sedation and hypotension and is available in patch form. Fluphenazine, a typical antipsychotic, is effective but carries risk of extrapyramidal symptoms and tardive dyskinesia. Aripiprazole has growing evidence and requires metabolic monitoring. Risperidone is effective but associated with weight gain and prolactin elevation. Topiramate has modest evidence but may cause cognitive side effects.
| Medication | Class | FDA Approved for Tics | Key Advantages | Key Side Effects |
|---|---|---|---|---|
| Guanfacine | Alpha-2 agonist | No | First-line; also treats comorbid ADHD | Sedation, hypotension |
| Clonidine | Alpha-2 agonist | No | Available as patch; helps with sleep | Sedation, hypotension, rebound hypertension |
| Aripiprazole | Atypical antipsychotic | Yes (Tourette's, 6+) | Growing evidence in youth | Metabolic effects, akathisia |
| Risperidone | Atypical antipsychotic | No | Effective for tic reduction | Weight gain, prolactin elevation |
| Fluphenazine | Typical antipsychotic | No | Effective | EPS, tardive dyskinesia risk |
| Topiramate | Anticonvulsant | No | Weight-neutral | Cognitive dulling, word-finding difficulty |
Treatment of Comorbidities
For comorbid ADHD, stimulants are safe and effective and do not worsen tics in most patients, contrary to older beliefs. For OCD, SSRIs such as fluvoxamine and sertraline and/or exposure and response prevention are appropriate. Rage attacks may respond to CBIT, alpha-2 agonists, or low-dose antipsychotics.
PANDAS/PANS
When a post-infectious autoimmune etiology is suspected, antibiotics for active streptococcal infection are appropriate. Immunomodulatory treatments such as IVIG and plasmapheresis remain controversial and are reserved for severe, clearly autoimmune cases. Behavioral and psychiatric treatment of symptoms is always appropriate regardless of etiology.
Clinical Pearls
The guiding principle in Tourette syndrome is to treat what impairs most; ADHD and OCD often cause more functional impairment than the tics themselves. CBIT is first-line treatment and is as effective as medication, so all clinicians treating tic disorders should be familiar with or able to refer for this intervention. Stimulants are safe in children with tics and ADHD, as the old contraindication has been disproven by controlled trials. Tics typically peak around ages 10-12 and improve spontaneously in the majority of patients, making reassurance and watchful waiting appropriate for mild tics.
References
- Pringsheim T, et al. "Practice Guideline Recommendations Summary: Treatment of Tics in People with Tourette Syndrome and Chronic Tic Disorders." Neurology. 2019;92(19):896-906.
- Piacentini J, et al. "Behavior Therapy for Children with Tourette Disorder: A Randomized Controlled Trial." JAMA. 2010;303(19):1929-1937.
- Bloch MH, Leckman JF. "Clinical Course of Tourette Syndrome." Journal of Psychosomatic Research. 2009;67(6):497-501.
- Martino D, Leckman JF. Tourette Syndrome. New York: Oxford University Press; 2013.